The present invention is directed to a sequence generator system for generating a sequence of data corresponding to notes to be sounded by an electronic musical instrument, and particularly to such a sequence generator for use in an electronic musical instrument wherein a serial data stream is generated corresponding to notes actuated on the instrument, the sequence generator inserting a predetermined sequence of data into the serial data stream.
Electronic musical instruments of the type wherein a serial data stream is generated corresponding to notes actuated are generally known. Generally speaking, such instruments utilize multiplexers or similar scanning means to generate such a sequence of serial data. In a keyboard-type of instrument, one such scanning or multiplexing means is generally provided for each manual or keyboard of the instrument so as to generate separate serial data streams corresponding to the notes actuated on each manual or keyboard. Such known electronic musical instruments further include tone generating circuits responsive to the serial data stream for generating tones corresponding to the actuated notes.
Various arrangements have heretofore been provided for generating an additional data sequence corresponding, for example, to an arpeggio effect. Such systems include means for inserting this further data sequence into the serial data stream fed to the tone generating circuits, to cause the generation of a sequence of notes corresponding for example to an arpeggio effect. Heretofore, however, such arpeggio or other like accompaniment effect generating systems have depended upon relatively large memory components such as ROMs, to provide pre-programmed data sequences for insertion into the serial data stream in order to provide the desired effect. Accordingly, such systems have generally been limited in the number and type of effects available by constraints of the capacity of available memory circuits such as ROMs and also by the limited alternatives available for programming such memory components. Moreover, relatively large ROM-type memory components are relatively expensive, the programming thereof adding further expense to the production of the electronic musical instrument. Hence, only electronic musical instruments in a relatively highprice range have heretofore utilized such accompaniment generating systems.